Genotypic and phenotypic diversity of Lactobacillus delbrueckii subsp. lactis strains of dairy origin.

Eighty-nine strains of Lactobacillus delbrueckii subsp. lactis isolated from Italian hard and semi-hard cheeses and artisan starter cultures were characterised by phenotypic and genotypic methods. Phenotypic diversity was evaluated by studying biochemical characteristics (i.e. acidifying and peptidase activities) of technological interest. Genotypic diversity was evidenced by RAPD-PCR and pulsed field gel electrophoresis (PFGE). Phenotypic characterisation indicated a wide variability of the acidifying activity within Lact. delbrueckii subsp. lactis. Although the data was variable, it allowed us to evidence groups of strains with different acidifying properties, especially in terms of acidification intensity. Concerning peptidase activity, Lact. delbrueckii subsp. lactis showed a homogeneously high x-prolil-dipeptidil-aminopeptidase activity and a considerable but more heterogeneous lysil-aminopeptidase activity. The increased resolution obtained by the use of two molecular typing techniques, i.e. RAPD-PCR and PFGE, allowed to widen the level of strain heterogeneity. Technological and ecological pressures are determinant in selecting Lact. delbrueckii subsp. lactis sub-populations which are more functional to the different cheese technologies.

Some new methyl-8-methoxypsoralens: synthesis, photobinding to DNA, photobiological properties and molecular modelling.

The tricyclic structure of known natural photochemotherapeutic drugs such as 8-methoxypsoralen and 5-methoxypsoralen is often taken as a model in the search of new photosensitizer agents with less phototoxic and mutagenic effects. This paper describes the synthesis, characterization, photobinding to DNA, photobiological properties and computational chemistry of some 8-methoxypsoralen derivatives bearing two or three methyl groups at the key positions of the two photoactive double bonds. Results showed that photoreactivity and photobiological behaviour depend on the pattern of methyl substitutions. Antiproliferative activity in cell lines shows good correlation with DNA interaction data.

[Immune responses of IgG, IgA and anti-CagA IgG to Helicobacter pylori in dyspeptic and peptic ulcer patients]. / Dyspepsiás és pepticus fekélybetegek Helicobacter pylori-ellenes specifikus IgG, IgA és anti-CagA IgG immunválasza.

The anti-H. pylori IgG, IgA, and anti CagA responses in dyspeptic patients have been evaluated. Of 481 patients 76% tested positive for IgG anti-H. pylori, 57% for anti-CagA, and 52% IgA for anti H. pylori. There was a significant age-related increase in IgG anti-H. pylori and IgA anti-H. Pylori prevalence, whereas anti-CagA positives were unreliable in this respect. The IgG seropositivity was the highest (93%) in duodenal ulcers (DU), 82% in antral gastritis and/or bulbitis (AG +/- /B), and 71% in gastric ulcer (GU). GU patients compared with DU and AG +/- /B ones tended to have the highest IgA anti-H. pylori prevalence (78% vs. 66% and 61%). The anti-CagA seropositivity was the most pronounced (80%) in DU followed by GU (72%) and AG +/- /B (68%). It is suggested that the serodiagnosis including IgG, IgA anti-H. pylori and anti-CagA determinations can not replace endoscopy in revealing the exact nature of gastroduodenal lesions. IgA anti-H. pylori determination in female patients with GU can be a valuable diagnostic tool. It is stated that in Hungary the prevalence of CagA positive H. pylori strains in anti-H. pylori IgG positive dyspeptic patients is 85%.

4'-Methyl derivatives of 5-MOP and 5-MOA: synthesis, photoreactivity, and photobiological activity.

The synthesis and photobiological activity of four new 4'-methyl derivatives of 5-MOP (5-methoxypsoralen) and 5-MOA (5-methoxyangelicin), i.e., 4,4'-dimethyl-5-methoxypsoralen, 3,4'-dimethyl-5-methoxypsoralen, 4,4'-dimethyl-5-methoxyangelicin, and 3,4'-dimethyl-5-methoxyangelicin, are described. All these compounds photobind efficiently to DNA. The DNA-photobinding process was investigated using various nucleic acid structures such as double-helix DNA, bacterial DNA, and synthetic polydeoxyribonucleotides. Photoreaction experiments showed that, unlike 8-MOP (8-methoxypsoralen) and 5-MOP, both angular derivatives bind thymine and cytosine with the same efficiency. The principal nucleoside-psoralen monoadducts were isolated and characterized after enzymatic digestion or acid hydrolysis. Biological activity studies revealed a good correlation with the extent of covalent photoaddition. Moreover, the two angular derivatives and the 4,4'-dimethyl-5-methoxypsoralen were unable to induce skin erythema, in striking contrast with the reference drugs, 8-MOP and 5-MOP; only the 3,4'-dimethyl-5-methoxypsoralen caused erythema, although to a substantially lower extent than that induced by the two parent compounds.

Synthesis and characterization of new methylpsoralens as potential photochemotherapeutic agents.

Three new psoralens with methyl groups on carbons involved in their reactive double bonds (compounds 9-11 in Scheme 1) were synthesized from the corresponding 7-hydroxycoumarins by cyclization of acetonyl derivatives of the latter in an alkaline medium. In preliminary tests, the new methyl-substituted psoralens exhibited considerable interaction in the dark with DNA, good photoreactivity against the macromolecule, and also interesting antiproliferative activity.

Synthesis and photobiological activity of new methylpsoralen derivatives.

The synthesis and the photobiological activity of two new derivatives of psoralen (3,4'-dimethylpsoralen and 3,4',8-trimethylpsoralen) has been described. They are congeners of the monofunctional linear furocoumarin 3,4'-dimethyl-8-methoxypsoralen. Both compounds bind very efficiently to DNA, the extent of this process being modulated by the nature of substituents at position 8. The number of photolesions is linearly related to adenine-thymine content of the nucleic acid which indicates lack of specificity for particular sequences of the nucleic acid. The structural arrangement of DNA (single stranded, double stranded, nucleosomes and chromatin) plays an additional role in affecting the photobinding process. Unlike their 8-methoxy congener the new derivatives cross-link DNA to a substantial extent. Their photobiological properties, including erythema formation, reflect very closely those of 8-methoxypsoralen (8-MOP). The conclusion can be drawn that 3,4'-dimethyl-8-MOP represents a unique derivative in its family.

Photobiological activity of 3,4'-dimethyl-8-methoxypsoralen, a linear furocoumarin with unusual DNA-binding properties.

The furocoumarin derivative 3,4'-dimethyl-8-methoxypsoralen (DMe-8-MOP) exhibits remarkable antiproliferative activity, but is devoid of skin phototoxicity. To gain insight into this peculiar behaviour we investigated non-covalent and covalent binding of DMe-8-MOP to calf thymus DNA, along with DNA-synthesis inhibition and mutagenic activity. The non-covalent interaction of DMe-8-MOP with the nucleic acid is quite poor as shown by equilibrium dialysis, spectroscopic, chiroptical and hydrodynamic techniques. However, it exhibits relevant photobinding ability to DNA using both isolated nucleic acid samples and cellular systems. Unlike the large majority of congeners, DMe-8-MOP undergoes predominantly photochemical monoaddition to the double helical polynucleotide. Upon examination of the products obtained by enzymatic hydrolysis of DMe-8-MOP photomodified DNA, the formation of an unusual furan side adduct is proposed, which could account for the peculiar photochemical and photobiological properties of the 3,4'-dimethyl furocoumarin derivative.

Diethylaminopropionamido-hydroxy-anthraquinones as potential anticancer agents: synthesis and characterization.

A number of new 9,10-anthracenediones were obtained, bearing one or two hydroxyl groups and one positively charged side chain at different positions of the aromatic ring system (compounds 1-5 in Chart 1). These derivatives resemble the anticancer agents mitoxantrone and ametantrone. The synthesis started from dihydroxy- or amino-hydroxy-9,10-anthracenediones, which were converted into the nitro-derivatives. After reduction to the corresponding amines and acylation with 3-chloropropionyl chloride, substitution with diethylamine led to the final diethylaminopropionamido derivatives. The new anthracenediones cause a quite relevant inhibition of cell growth in vitro and will be tested as possible anticancer agents.

Bis-substituted hydroxy-anthracenediones: DNA binding and biological activity.

Three new hydroxy-9,10-anthracenedione derivatives (compounds 1-3 in Figure 1), bearing two charged or polar side chains at positions 2 and 4/5 of the tricyclic system, have been investigated for their DNA binding, cytotoxic and genotoxic activity. The interaction mode with nucleic acids is intercalative for compounds 1 and 2, while external and intercalative binding probably coexist for compound 3. Complexation of the nucleic acid occurs in all cases in a cooperative manner, so that drug binding favours further binding to double helical DNA. The scale of the intrinsic binding constant is discussed in terms of the nature and position of the side chain. Cell growth and DNA synthesis inhibition data match quite well with DNA affinity. Alkaline elution experiments show a correlation between drug cytotoxicity and DNA damage. Our results indicate that the position and number of OH groups, as well as of charged side chains, play an important role in modulating drug affinity for DNA and the consequent biological effects.

Antitumor activity of new anthraquinone derivatives.

Seven new 9,10-anthracenedione derivatives bearing positively-charged side chains at different positions of the condensed ring system have been investigated in their interaction with DNA and their biological effects, including antitumor activity in the P 388 mouse miniscreen. The drug's affinity for DNA was found to be related to the efficacy of inhibition of cell growth and nucleic acid synthesis for a number of cell lines. Moreover, alkaline elution experiments showed a close relationship between mutagenic potential and cytotoxicity. With the exception of one, all compounds behaved like intercalating agents, as shown by the unwinding of supercoiled plasmid DNA. DNA appeared, therefore, to be the more important target for drug action. The marginal in vivo activity shown by two substances in this series suggests a number of possible structural modifications which may increase their therapeutic efficacy.

A search for potential antitumor agents: biological effects and DNA binding of a series of anthraquinone derivatives.

In an effort to establish a relationship between mechanism of binding and affinity to DNA, cytotoxic activity, and genotoxic activity, we have studied four new anthracenedione derivatives bearing charged side chain groups at various positions of the polycyclic aromatic system. Cytotoxicity, genotoxicity, and thermodynamic DNA binding parameters were shown to be directly related, indicating the polynucleotide as an important target for drug action, rather than a minor, subterminal interacting site. This finding was further supported by the observation of extensive anthraquinone accumulation occurring in the nuclear compartment. The relative binding affinities of the drugs are discussed in terms of nature and position of side-chain substituents. Different binding modes were found: three compounds intercalate into the nucleic acid double helix, and one interacts with the exterior of the macromolecule. The biological results suggest that the mode of complex formation plays a less relevant role than DNA binding efficiency.

Photobiological properties of some water-soluble 5-MOP and 8-MOP derivatives.

The photobiological properties of a number of water-soluble psoralen derivatives have been investigated. The compounds are characterized by the presence of protonated diethylaminoalkyloxy side-chains at position 5 or 8. Thus they are strictly related to the photochemotherapeutic agents 5-MOP and 8-MOP. Inhibition of DNA synthesis by the above compounds has been evaluated in mouse skin in vivo and in Ehrlich ascites tumor cells. In the latter experiments, inhibition of tumor transmitting capacity has been demonstrated by injection of irradiated cells into healthy animals. Finally, skin erythema formation has been studied in albino guinea pigs. The photobiological responses were quite remarkable in all cases. In general, derivatives at position 5 exhibit stronger antiproliferative effects, while the 8 isomers display higher skin phototoxicity.